drop table g01;
drop table g02;
drop table g03;
drop table c01;
drop table c02;
drop table c03;
drop table s01;

create table g01(gnum) as select * from grade;
create table g02(gnum) as select num, 100 as cnum, color from grade;
create table g03 as select * from grade;
create table c01(gnum, cnum) as select * from class;
create table c02(gnum, cnum) as select gnum, num, 200 as snum, charge from class;
create table c03 as select * from class;
create table s01(gnum, cnum, snum) as select gnum, cnum, num, name from student;